The present invention relates to surgical instruments and in particular to surgical instruments that include guiding surfaces for saws and other cutting tools used in bone surface preparation.
Many surgical instruments are fixed in a known position relative to a patient, particularly when used in bone surface preparation. One example is a cutting block. Cutting blocks are typically affixed to a patient's bone in a position such that they can guide cutting and resection of the bone surface for receiving an implant.
Existing cutting blocks may include a guide, recess or cutting groove for the cutting tool, such as a saw, used for cutting and resectioning in order to correctly position and guide the cutting tool during the surgical procedure.
In an existing cutting block, the cutting block has a top surface for guiding a saw blade during a step in an orthopaedical surgical procedure, such as distal femoral resection. The cutting block also includes a top plate which defines a cutting groove for receiving the saw and which can also be used as a guide during distal femoral resectioning. To achieve this, the top plate is movable between an extended, first position to a closed, second position. In the first position, the top plate defines the cutting groove. When the top plate is in the second position, the top plate is contiguous with a main body of the cutting block to define a top, distal surface for guiding the cutting tool. A surgeon can use either the top surface or the cutting groove as a guide for the cutting tool. The choice of either the top surface or the cutting groove is usual one of personal preference for the surgeon.
Historically, the top plate is locked into the first and second positions by means of two pins with indents which act against a spring loaded ball bearing which indexes the position of the plate with respect to the main body of the cutting block.